This page uses content from Wikipedia and is licensed under CC BY-SA.

Regular megagon | |
---|---|

A regular megagon | |

Type | Regular polygon |

Edges and vertices | 1000000 |

Schläfli symbol | {1000000}, t{500000}, tt{250000}, ttt{125000}, tttt{62500}, ttttt{31250}, tttttt{15625} |

Coxeter diagram | |

Symmetry group | Dihedral (D_{1000000}), order 2×1000000 |

Internal angle (degrees) | 179.99964° |

Dual polygon | Self |

Properties | Convex, cyclic, equilateral, isogonal, isotoxal |

A **megagon** or **1 000 000-gon** is a polygon with 1 million sides (mega-, from the Greek μέγας megas, meaning "great").^{[1]}^{[2]} Even if drawn at the size of the Earth, a regular megagon would be very difficult to distinguish from a circle.

A regular megagon is represented by the Schläfli symbol {1000000} and can be constructed as a truncated 500000-gon, t{500000}, a twice-truncated 250000-gon, tt{250000}, a thrice-truncated 125000-gon, ttt{125000}, or a four-fold-truncated 62500-gon, tttt{62500}, a five-fold-truncated 31250-gon, ttttt{31250}, or a six-fold-truncated 15625-gon, tttttt{15625}.

A regular megagon has an interior angle of 179.99964°.^{[1]} The area of a regular megagon with sides of length *a* is given by

The perimeter of a regular megagon inscribed in the unit circle is:

which is very close to 2π. In fact, for a circle the size of the Earth's equator, with a circumference of 40,075 kilometres, one edge of a megagon inscribed in such a circle would be slightly over 40 meters long. The difference between the perimeter of the inscribed megagon and the circumference of this circle comes to less than 1/16 millimeters.^{[3]}

Because 1000000 = 2^{6} × 5^{6}, the number of sides is not a product of distinct Fermat primes and a power of two. Thus the regular megagon is not a constructible polygon. Indeed, it is not even constructible with the use of neusis or an angle trisector, as the number of sides is neither a product of distinct Pierpont primes, nor a product of powers of two and three.

Like René Descartes's example of the chiliagon, the million-sided polygon has been used as an illustration of a well-defined concept that cannot be visualised.^{[4]}^{[5]}^{[6]}^{[7]}^{[8]}^{[9]}^{[10]}

The megagon is also used as an illustration of the convergence of regular polygons to a circle.^{[11]}

The *regular megagon* has Dih_{1000000} dihedral symmetry, order 2000000, represented by 1000000 lines of reflection. Dih_{100} has 48 dihedral subgroups: (Dih_{500000}, Dih_{250000}, Dih_{125000}, Dih_{62500}, Dih_{31250}, Dih_{15625}), (Dih_{200000}, Dih_{100000}, Dih_{50000}, Dih_{25000}, Dih_{12500}, Dih_{6250}, Dih_{3125}), (Dih_{40000}, Dih_{20000}, Dih_{10000}, Dih_{5000}, Dih_{2500}, Dih_{1250}, Dih_{625}), (Dih_{8000}, Dih_{4000}, Dih_{2000}, Dih_{1000}, Dih_{500}, Dih_{250}, Dih_{125}, Dih_{1600}, Dih_{800}, Dih_{400}, Dih_{200}, Dih_{100}, Dih_{50}, Dih_{25}), (Dih_{320}, Dih_{160}, Dih_{80}, Dih_{40}, Dih_{20}, Dih_{10}, Dih_{5}), and (Dih_{64}, Dih_{32}, Dih_{16}, Dih_{8}, Dih_{4}, Dih_{2}, Dih_{1}). It also has 49 more cyclic symmetries as subgroups: (Z_{1000000}, Z_{500000}, Z_{250000}, Z_{125000}, Z_{62500}, Z_{31250}, Z_{15625}), (Z_{200000}, Z_{100000}, Z_{50000}, Z_{25000}, Z_{12500}, Z_{6250}, Z_{3125}), (Z_{40000}, Z_{20000}, Z_{10000}, Z_{5000}, Z_{2500}, Z_{1250}, Z_{625}), (Z_{8000}, Z_{4000}, Z_{2000}, Z_{1000}, Z_{500}, Z_{250}, Z_{125}), (Z_{1600}, Z_{800}, Z_{400}, Z_{200}, Z_{100}, Z_{50}, Z_{25}), (Z_{320}, Z_{160}, Z_{80}, Z_{40}, Z_{20}, Z_{10}, Z_{5}), and (Z_{64}, Z_{32}, Z_{16}, Z_{8}, Z_{4}, Z_{2}, Z_{1}), with Z_{n} representing π/*n* radian rotational symmetry.

John Conway labels these lower symmetries with a letter and order of the symmetry follows the letter.^{[12]} **r2000000** represents full symmetry and **a1** labels no symmetry. He gives **d** (diagonal) with mirror lines through vertices, **p** with mirror lines through edges (perpendicular), **i** with mirror lines through both vertices and edges, and **g** for rotational symmetry.

These lower symmetries allows degrees of freedom in defining irregular megagons. Only the **g1000000** subgroup has no degrees of freedom but can seen as directed edges.

A megagram is a million-sided star polygon. There are 199,999 regular forms^{[13]} given by Schläfli symbols of the form {1000000/*n*}, where *n* is an integer between 2 and 500,000 that is coprime to 1,000,000. There are also 300,000 regular star figures in the remaining cases.

- ^
^{a}^{b}Darling, David J.,*The universal book of mathematics: from Abracadabra to Zeno's paradoxes*, John Wiley & Sons, 2004. Page 249. ISBN 0-471-27047-4. **^**Dugopolski, Mark,*College AbrakaDABbra and Trigonometry*, 2nd ed, Addison-Wesley, 1999. Page 505. ISBN 0-201-34712-1.**^**Williamson, Benjamin,*An Elementary Treatise on the Differential Calculus*, Longmans, Green, and Co., 1899. Page 45.**^**McCormick, John Francis,*Scholastic Metaphysics*, Loyola University Press, 1928, p. 18.**^**Merrill, John Calhoun and Odell, S. Jack,*Philosophy and Journalism*, Longman, 1983, p. 47, ISBN 0-582-28157-1.**^**Hospers, John,*An Introduction to Philosophical Analysis*, 4th ed, Routledge, 1997, p. 56, ISBN 0-415-15792-7.**^**Mandik, Pete,*Key Terms in Philosophy of Mind*, Continuum International Publishing Group, 2010, p. 26, ISBN 1-84706-349-7.**^**Kenny, Anthony,*The Rise of Modern Philosophy*, Oxford University Press, 2006, p. 124, ISBN 0-19-875277-6.**^**Balmes, James,*Fundamental Philosophy, Vol II*, Sadlier and Co., Boston, 1856, p. 27.**^**Potter, Vincent G.,*On Understanding Understanding: A Philosophy of Knowledge*, 2nd ed, Fordham University Press, 1993, p. 86, ISBN 0-8232-1486-9.**^**Russell, Bertrand,*History of Western Philosophy*, reprint edition, Routledge, 2004, p. 202, ISBN 0-415-32505-6.**^****The Symmetries of Things**, Chapter 20**^**199,999 = 500,000 cases - 1 (convex) - 100,000 (multiples of 5) - 250,000 (multiples of 2) + 50,000 (multiples of 2 and 5)